Rhinoceros3D – McNeel CAD environment that supports complex surfacing and with plugins can be used for controlling robots, CAM, physics modeling, etc.
Food 4 Rhino – Biggest site to find plugins to extend Rhino
Grasshopper – parametric design tools to extend Rhino
Fusion 360 – Autodesk suite of CAD/CAM tools
3D Printing and Fabrication Tools
Additive 3D Printing Guidelines – Good overview article on Core77
Slicer – Autodesk fabrication utility that enables physical creation of CAD model through various construction methods, stacked slices, interlocking slices, etc. This utility is included in Fusion 360 and as a stand-alone free utility.